As analyzers that use a sample and a reagent, have a mechanism for dispensing those into a reaction vessel, and detect the liquid that has reacted within the reaction vessel, there are various analyzers especially in the fields of medicine, biotechnology, and the like; for example, there is an automatic analyzer for detecting particular biological substances, chemical substances, and the like contained in a sample using blood, serum, urine, or the like as the sample. In this automatic analyzer, to achieve the realization of inspections having high accuracy and high reliability, further improvement in analysis accuracy is being attempted. Especially with a method of rinsing a dispensing nozzle, if the method is insufficient, the adsorbed substances may be detached, resulting in interfusion with another sample in next dispensing. This is generally called carryover and affects measurement results. Moreover, when only a small amount of a sample can be collected as children and the elderly, or to reduce patients' burden and the like, or to reduce the amounts of reagents used, the amounts of samples and reagents used will be further decreased from now on, and the tendency toward reduction in dispensation amounts of samples and reagents will be stronger. That is, more accurate dispensation of samples and reagents will be necessary than before. Coupled with the tendency toward reduction in dispensation amounts of samples and reagents, sufficient rinsing of dispensing nozzles used for dispensing samples and reagents is necessary for the prevention of carryover and contamination. For such problems, rinsing a dispensing nozzle using rinse water or rinse liquid is known, and various methods have been proposed. For example, the method disclosed in Patent Document (JP-1994-207944-A) is one in which a reagent vessel unit in which a reagent housing section for housing reagents and a rinse liquid housing section for housing rinse liquids used for the reagents are put together is housed within a reagent disk, a rinse tank for rinsing a dispensing nozzle is provided separately, the dispensing nozzle is temporarily moved onto the reagent disk to suction a rinse liquid, and the dispensing nozzle is then moved to the rinse tank to discharge the rinse liquid, thereby rinsing the dispensing nozzle.